Performance of Pillar and Upright Form Peach Trees Grown in a Central Leader or Multiple Leader Orchard System at Various Planting Densities

Abstract

Peach trees with a pillar (P) (columnar) or upright (UP) growth habit were planted at four in-row spacings (1.5, 2.0, 4.0, and 6.0 m) in 1999 and trained to a central leader or multiple leader system to evaluate their performance in an orchard environment. A standard (S) form peach cultivar (`Harrow Beauty') was included for comparison. In this replicated study using a split-split-split plot design, one-half of the trees were summer pruned (SP) 6 weeks before harvest in each growing season from 2001 to 2003. Growth habit, tree spacing, and SP had a significant effect on tree growth and time necessary for dormant pruning. Growth habit and spacing also affected time required to summer prune. Total pruning time for all growth habits was significantly greater for SP trees compared to non-SP trees. Cumulative yields per tree were greater for UP and S habit trees than P trees over the first four seasons. Per tree yields increased as the in-row spacing increased but were decreased slightly by SP. UP trees consistently produced larger size fruit than P or S trees. Potential yields per ha and pruning times based on projected best tree spacings will be presented. UP form trees provide a good transition for growers going from low-density to high-density peach systems, with significant advantages in yield and fruit quality.